Corn fields in Kansas are under threat from a disease called tar spot, caused by the fungus Phyllachora maydis. Recent confirmations of its presence span across several Kansas counties including Doniphan (6/26), Atchison (6/30), Jefferson (6/30), Brown (7/05), and Nemaha (7/28) counties.
Spotting the Disease
Tar spots appear as small, dark spots on corn plants. They can be found on healthy or dying plant parts like leaves and husks. This disease might be mistaken for insect droppings due to its black spot appearance. If you're unsure, consider reaching out to the K-State plant diagnostic clinic
Understanding Its Spread
This fungus lives in leftover corn pieces on the ground. Wind and rain can carry its spores to nearby fields, especially if the weather conditions are right.
Monitoring Growth Stages
It's important to know your corn's growth stage. Applying treatments when the disease is first seen, especially around the VT or "tassel" stage, can be effective. But if you wait too long, it might be too late. A corn growth guide
The Role of Moisture
Wet conditions, like recent rains, make it easy for tar spot to grow. If your corn is watered a lot, be on high alert! The upcoming wet weather will also help the disease spread.
Fighting Back with Fungicides
Fungicides can help, but timing is key. Apply them when the disease is active and your corn is nearing certain growth stages like VT/R1. Remember, scouting is crucial, especially if rain keeps coming. Some fungicides work best against tar spot. For a list of effective ones, check out the Crop Protection Network.
If you think your field has tar spot, let's track it. Call 785-477-0171 or send a sample to the K-State Plant Disease Diagnostic Lab.
Photo Credit: gettyimages-luc-pouliot
Categories: Kansas, Crops, Corn